I have the opportunity to purchase an 8.1 liter for a reasonable price, but I do not know anything about them. Are they easy to install or is it going to take a computer genius. I wish to install it in my 71 chevelle, or should I just go to a 454 or 502 ???. Any help would be appreciated, Thanks Rudy graemlins/waving.gif

are you talking about a 496? (8.1 is rough 495 CI) It should be same as going to any another big block, execpt the 572 which as raised ports, then it just gets messy smile.gif

The 8.1 motors only run with fuel injetion. Do a search on this it has been discussed before. It's a shame, there are a lot of these out there for reasonable dollars.

I would love to get my hands on one and play with it by putting a complete top end off a Mark IV motor on it using spacer plates..

pdq67

I think the biggest problem is the change in the head bolt pattern, not sure if ahead swap is feasable.

John

*feels dumb* whats an 8.1, never heard of it before?

I still don't think they make manifold for those heads so you're stuck with FI and computers, harnessess and stuff.

Someone could make an aluminum intake for a 750 to 1000 or even two fours which would be a killer street or torque monster.

Heads are not interchangeable with conventional BBC heads, the pattern was changed and two bolts added.

Intake ports are similar to an LS1 but bigger. A hand fabbed intake WOULD work. The heads would work well to 7000 plus IMO. There is still provision on the cam to drive a distributor.

Oil pan is aluminum, would need mods to fit anything with a crossmember probably.

I had one.

Parts are expensive. Rods are longer, it is a tall deck configuration. 4.250 bore x 4.370 stroke.

Rings are an odd metric package. I believe bearings are still interchangeable with old style BBC's.

It is not really easy conversion material. But if a guy had a TIG, some sheet aluminum, some time, and the inclination....
It could be a neat deal.

There was a listing on Ebay for a guy/company right down in Salem NJ, had about 20 of these - GM Van/Truck takeouts. I think the early ones had very low tension rings and tended to use oil, kinda like the early 502's. He was selling these for about 300.00. I was half tempted to buy one of these, re-ring it and attempt a fab'd intake. It wouldn't be very scientific, but with the long stroke to fix any holes in the torque curve, plus the fact that the ports are symetrical, you could probably get away with a low rise tunnel ram type manifold, something with near-equal length runners,maybe about 4 inches long connected to a rec.shaped plenum. Fairly sure the exhaust ports are in the same location though, stock BBC headers should bolt up. Also, can't comment on the balancer and water pump, but I would assume these would need to be changed to run pulley and v-belts.

Someone needs to take the plunge on one of these.

Thanks to everybody on your input, its sounds like the 8.1 would be nice to mess with, but not realistic to to do anything with presently. If the after market industry would get involved, it might be a nice engine.

Rudy graemlins/beers.gif

I know that Jake and I have chatted about this but I really can't see all that much of a hassle installing an old style topend on one..

Plug the existing headbolt pattern's holes and line up an old head, make a hardened thin drill bit bushing so the correct size bit can be used and get the old trusty 1/2" hand drill out and use the old head as a headbolt pattern guide!!

Carefully re-tap the new holes and then you would probably need to use intake spacers like is used to install a regular deck height motor intake on a tall deck motor.

Jake, am I missing something??

And btw, does the 8.1 L motor by any chance have siamesed cylinders b/c if it did, you could make a BIG motor out of it real EASY, imho!!!

(Jake, I forgot if you told me this already or not so please bear with me here)..

Say, 4.5" b x 4.37" s = 556"er - BIG!!!!!

pdq67